1. Field of the Invention
The present invention relates to an air gun for producing nonwoven fabrics, and particularly to an air gun for producing nonwoven fabrics in which at the start of operation, a filament can be easily introduced.
2. Description of the Related Art
As an air gun producing nonwoven fabrics, particularly, an air gun for drawing and receiving filaments spun from spinning nozzles at high speed and putting them on an air flow and delivering them onto a screen belt to form a web which is intermediate of nonwoven fabric, there has been heretofore proposed a configuration which includes an inlet for receiving filaments spun from spinning nozzles, a carrier path for putting said filaments introduced through said inlet to deliver them, and a compressed air blow port which is opened in the midst of said carrier path to jet air from a compressed air source into the carrier path.
In such an air gun as described, more specifically, an accelerating pipe constituting a part of the carrier path is connected on the downstream side.
When compressed air is blown out of the compressed air blow port, a negative pressure is generated in the filament inlet to suck filaments from the spinning nozzle (hereinafter referred to as an ejector performance). In addition, when compressed air is blown out of the compressed air blow port, a traction is applied to the filament downstream from that portion to draw and deliver the filament (hereinafter referred to as a receiving performance).
In such an air gun as described, it is desirable for economical operation and prevention of noises caused by air to maintain the receiving performance and reduce an amount of drive air.
As the method for maintaining the receiving performance and reducing the amount of drive air, a method for reducing an inside diameter of an accelerating pipe to increase flow velocity within the pipe is employed.
However, if the inside diameter of the accelerating pipe is reduced, pressure loss increases, and pressure of filament inlet increases by that portion to deteriorate the ejector performance and make it difficult to introduce filaments at the start of operation.